Spatial Hierarchy & Topology

The Inventory & WMS domain manages the physical distribution of goods by representing warehouse facilities as a strict topological hierarchy.

1. Spatial Topology Hierarchy

Every physical item must reside within an addressable bin location. Bins are modeled inside a vertical tree structure:

[Warehouse] (General facility node)
   └── [Zones] (Functional areas: Receiving, Bulk, Picking, Staging, Packing)
         └── [Aisles] (Corridors within a zone)
               └── [Racks] (Vertical grid structures)
                     └── [Shelves] (Horizontal levels)
                           └── [Bins] (Terminal, coordinate-addressed storage addresses)

2. Location Types & Functional Statuses

Bins are categorized by operational roles, which restrict how the system processes inventory inside them:

• Pickable Bins: High-accessibility locations designated for fast extraction. Outbound picking requests route operators here first.
• Reserve Bins: High-capacity bulk storage locations (e.g., top shelves of racks) used to hold surplus stock. Unpickable by standard order dispatch.
• Quarantine Bins: Isolated locations for damaged, expired, or unverified items. Items placed in quarantine are automatically excluded from the Available to Promise (ATP) calculation.
• Transit / In-Transit Bins: A virtual location category used to hold stock that has been checked out of a source bin but has not yet been checked into a destination bin.
• Scrap / Loss Bins: A virtual location used to absorb inventory shrinkage or write-offs. Moving stock here records it as a loss.
• Production / Staging Bins: Staging areas dedicated to raw materials feeding manufacturing processes or work-in-progress (WIP).

3. Capacity & Physical Constraints

To prevent spatial overload and hazardous placement, the system validates the following attributes before authorizing stock movements:

• Volume Limits: The maximum cubic space a bin can occupy.
• Weight Capacity: The physical weight threshold a shelf can sustain.
• Dimension Boundaries: Height, width, and depth limits ensuring packages fit the bin coordinates.
• Pick-Sequence Traversal Paths: Bins are assigned sequential path indexing coordinates. Picking routing algorithms sort pick lists using these indices, ensuring physical operators follow the shortest path through the facility.

4. Location Addressing & Layout Flows

To support automated picking guides and automated guided vehicles (AGVs), the topological structure mandates strict coordinate formats and flow policies.

Coordinate Addressing Standard

Every Bin is identified by a standardized coordinate address string:

$$\text{Address Code} = \text{Warehouse} - \text{Zone} - \text{Aisle} - \text{Rack} - \text{Shelf} - \text{Bin}$$

For example, WH02-PICK-A04-R08-S2-B03 represents Warehouse 2, Picking Zone, Aisle 4, Rack 8, Shelf 2, Bin 3. These addresses map directly to barcode and RFID tags.

Warehouse Layout Flow Configurations

Putaway and Picking algorithms calculate optimal routes based on the general physical layout flow pattern of the facility:

• U-Shaped Flow: Receiving and shipping docks are adjacent to each other. Materials flow in a semi-circle, sharing resources at receiving/shipping docks. High-velocity items are kept near the base of the “U” to minimize travel.
• Straight-Through Flow: Receiving and shipping docks are on opposite ends of the facility. Materials flow linearly, preventing cross-congestion.
• L-Shaped Flow: Receiving and shipping are perpendicular. Used to segregate staging spaces.